Copper(II) complexes of N,N′-bis(β-carbamoylethyl)trimethylenediamine in aqueous solution

Abstract

The interactions of the title ligand (bctn) with copper(II) in aqueous solution have been investigated by potentiometric and spectrophotometric techniques. The two protonation constants of the ligand at 25 °C and 0.2 mol dm^–3 Na[NO₃] are 10^9.29 and 10^7.06 dm³ mol^–1. Quantitative equilibrium studies of the stepwise reactions which precede the formation of [Cu(bctn)]²⁺ and the Cu–O to Cu–N bond rearrangements at the two amide sites are described in detail. Electronic spectra of the copper(II) chelates formed have been recorded and are discussed.